Method and apparatus for allocating resources to fdr-mode ue in a wireless communication system

ABSTRACT

A method for allocating resources by a Base Station (BS) in a wireless communication system is disclosed. The method includes configuring a Resource Block Group (RBG) dependent on whether a User Equipment (UE) operates in Full Duplex Radio (FDR) mode or Half Duplex (HD) mode, and allocating resources to the UE in units of the configured RBG. The RBG includes a plurality of Resource Blocks (RBs).

TECHNICAL FIELD

The present invention relates to wireless communication, and moreparticularly, to a method and apparatus for allocating resources to aUser Equipment (UE) in Full Duplex Radio (FDR) mode in a wirelesscommunication system.

BACKGROUND ART

Compared to conventional half duplex communication in which time orfrequency resources are divided orthogonally, full duplex communicationdoubles a system capacity in theory by allowing a node to performtransmission and reception simultaneously.

FIG. 1 is a conceptual view of a UE and a Base Station (BS) whichsupport Full Duplex Radio (FDR).

In the FDR situation illustrated in FIG. 1, the following three types ofinterference are produced.

Intra-device self-interference: Because transmission and reception takeplace in the same time and frequency resources, a desired signal and asignal transmitted from a BS or UE are received at the same time at theBS or UE. The transmitted signal is received with almost no attenuationat a Reception (Rx) antenna of the BS or UE, and thus with much largerpower than the desired signal. As a result, the transmitted signalserves as interference.

UE to UE inter-link interference: An Uplink (UL) signal transmitted by aUE is received at an adjacent UE and thus serves as interference.

BS to BS inter-link interference: The BS to BS inter-link interferencerefers to interference caused by signals that are transmitted betweenBSs or heterogeneous BSs (pico, femto, and relay) in a HetNet state andreceived by an Rx antenna of another BS.

DISCLOSURE OF INVENTION Technical Problem

An object of the present invention devised to solve the problem lies ona method for allocating resources by a Base Station (BS) in a wirelesscommunication system.

Another object of the present invention devised to solve the problemlies on a BS for allocating resources in a wireless communicationsystem.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present invention are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present invention could achieve will be more clearlyunderstood from the following detailed description.

Solution to Problem

The object of the present invention can be achieved by providing amethod for allocating resources by a Base Station (BS) in a wirelesscommunication system. The method includes configuring a Resource BlockGroup (RBG) dependent on whether a User Equipment (UE) operates in FullDuplex Radio (FDR) mode or Half Duplex (HD) mode, and allocatingresources to the UE in units of the configured RBG. The RBG includes aplurality of Resource Blocks (RBs).

When the UE operates in the FDR mode, the RBG may be configured asnon-contiguous RBs in a frequency domain. When the UE operates in the HDmode, the RBG may be configured as contiguous RBs in the frequencydomain. The number of the plurality of RBs included in the RBG may be 6,4, 3, or 2. Indexes of the non-contiguous RBs may be non-contiguous. Thenon-contiguous RBs of the RBG may be selected to minimizeInter-Modulation Distortion (IMD) affecting adjacent RBs.

In another aspect of the present invention, a BS for allocatingresources in a wireless communication system includes a processorconfigured to configure an RBG dependent on whether a UE operates in FDRmode or HD mode and allocate resources to the UE in units of theconfigured RBG. The RBG includes a plurality of RBs.

When the UE operates in the FDR mode, the processor may configure theRBG as non-contiguous RBs in a frequency domain. When the UE operates inthe HD mode, the processor may configure the RBG as contiguous RBs inthe frequency domain. The number of the plurality of RBs included in theRBG may be 6, 4, 3, or 2. Indexes of the non-contiguous RBs may benon-contiguous. The non-contiguous RBs of the RBG may be selected tominimize IMD affecting adjacent RBs.

Advantageous Effects of Invention

According to an embodiment of the present invention, communicationperformance can be increased by allocating resources in such a mannerthan non-linear components produced by the non-linearity of atransmitter may be reduced remarkably in a self-interference signalinherent to Full Duplex Radio (FDR) mode characterized by simultaneoustransmission and reception in the same frequency band.

It will be appreciated by persons skilled in the art that that theeffects that could be achieved with the present invention are notlimited to what has been particularly described hereinabove and otheradvantages of the present invention will be more clearly understood fromthe following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 is a view illustrating an exemplary network supportinghalf-duplex/full-duplex communication of a User Equipment (UE), proposedby the present invention;

FIG. 2 is a block diagram of a Base Station (BS) and a UE in a wirelesscommunication system;

FIG. 3 is a view illustrating exemplary radio frame structures in a 3rdGeneration Partnership Project (3GPP) Long Term Evolution(LTE)/LTE-Advanced (LTE-A) system as an exemplary wireless communicationsystem;

FIG. 4 is a view illustrating an exemplary resource grid for theduration of one Downlink (DL) slot in the 3GPP LTE/LTE-A system as anexemplary wireless communication system;

FIG. 5 is a view illustrating an exemplary Uplink (UL) subframestructure in the 3GPP LTE/LTE-A system as an exemplary wirelesscommunication system;

FIG. 6 is a view illustrating an exemplary Downlink (DL) subframestructure in the 3GPP LTE/LTE-A system as an exemplary wirelesscommunication system;

FIG. 7 is a conceptual view of transmission and reception links andSelf-Interference (SI) in a Full Duplex Radio (FDR) communicationsituation;

FIG. 8 is a view illustrating positions at which three interferencecancellation schemes are applied, in a Radio Frequency (RF) transmissionand reception end (or an RF front end) of a device;

FIG. 9 is a block diagram of a Self-Interference Cancellation (Self-IC)device in a proposed communication apparatus in an Orthogonal FrequencyDivision Multiplexing (OFDM) communication system environment based onFIG. 8;

FIG. 10 is a view illustrating exemplary 3rd Inter-Modulation Distortion(IMD) components generated in adjacent frequency bands during two-tonetransmission;

FIG. 11 is a view illustrating 3rd IMD components generated duringmulti-tone transmission;

FIG. 12 is a graph illustrating power spectral densities (dB) includingIMD components in an OFDM system;

FIG. 13 is a view comparing the power amounts of IMD components atrespective tones according to transmission BandWidths (BWs);

FIG. 14 is a view illustrating linear and non-linear SI components ateach tone in a conventional Resource Block Group (RBG) configurationrule;

FIG. 15 is a view illustrating linear and non-linear SI components ateach tone, when RBGs are configured non-uniformly;

FIG. 16A is a view illustrating an exemplary method for configuring RBGsby grouping 16 contiguous Physical Resource Blocks (PRBs) for RBG=4according to a first proposal (Proposal 1) of the present invention;

FIG. 16B illustrates an exemplary PRB mapping table laid out accordingto FIG. 16A;

FIG. 17A is a view illustrating an exemplary method for configuring RBGsby grouping 12 contiguous PRBs for RBG=4 according to Proposal 1 of thepresent invention;

FIG. 17B illustrates an exemplary PRB mapping table laid out accordingto FIG. 17A;

FIG. 18A is a view illustrating an exemplary method for configuring RBGsby grouping 64 contiguous PRBs for RBG=4 according to Proposal 1 of thepresent invention;

FIG. 18B illustrates an exemplary PRB mapping table laid out accordingto FIG. 18A;

FIG. 19A is a view illustrating an exemplary method for configuring RBGsby grouping 48 contiguous PRBs for RBG=4 according to Proposal 1 of thepresent invention;

FIG. 19B illustrates an exemplary PRB mapping table laid out accordingto FIG. 19A;

FIG. 20A is a view illustrating an exemplary PRB mapping of two PRBsselected from among four PRBs for RBG=2 in Embodiment 1-1, Embodiment1-2, Embodiment 1-3, and Embodiment 1-4 according to a second proposal(Proposal 2) of the present invention;

FIG. 20B illustrates an exemplary PRB mapping table laid out accordingto FIG. 20A;

FIG. 21A is a view illustrating an exemplary method for configuring RBGsby grouping 12 contiguous PRBs for RBG=3 according to Proposal 2 of thepresent invention;

FIG. 21B illustrates an exemplary PRB mapping table laid out accordingto FIG. 21A;

FIG. 22A is a view illustrating an exemplary method for configuring RBGsby grouping 24 contiguous PRBs for RBG=6 according to a third proposal(Proposal 3) of the present invention; and

FIG. 22B illustrates an exemplary PRB mapping table laid out accordingto FIG. 22A.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. In the following detailed description of the inventionincludes details to help the full understanding of the presentinvention. Yet, it is apparent to those skilled in the art that thepresent invention can be implemented without these details. Forinstance, although the following descriptions are made in detail on theassumption that a mobile communication system includes a 3^(rd)Generation Partnership Project (3GPP) Long Term Evolution (LTE) system,the following descriptions are applicable to other random mobilecommunication systems in a manner of excluding unique features of the3GPP LTE.

Occasionally, to prevent the present invention from getting vaguer,structures and/or devices known to the public are skipped or can berepresented as block diagrams centering on the core functions of thestructures and/or devices. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

Besides, in the following description, assume that a terminal is acommon name of such a mobile or fixed user stage device as a UserEquipment (UE), a Mobile Station (MS), an Advanced Mobile Station (AMS)and the like. And, assume that a Base Station (BS) is a common name ofsuch a random node of a network stage communicating with a terminal as aNode B (NB), an eNode B (eNB), an Access Point (AP) and the like.Although the present specification is described based on 3GPP LTE systemor 3GPP LTE-A system, contents of the present invention may beapplicable to various kinds of other communication systems.

In a mobile communication system, a UE is able to receive information inDownlink (DL) and is able to transmit information in Uplink (UL) aswell. Information transmitted or received by the UE may include variouskinds of data and control information. In accordance with types andusages of the information transmitted or received by the UE, variousphysical channels may exist.

The following descriptions are usable for various wireless accesssystems including Code Division Multiple Access (CDMA), FrequencyDivision Multiple Access (FDMA), Time Division Multiple Access (TDMA),Orthogonal Frequency Division Multiple Access (OFDMA), Single CarrierFrequency Division Multiple Access (SC-FDMA) and the like. CDMA can beimplemented by such a radio technology as Universal Terrestrial Radioaccess (UTRA), CDMA 2000 and the like. TDMA can be implemented with sucha radio technology as Global System for Mobile communications/GeneralPacket Radio Service/Enhanced Data Rates for GSM Evolution(GSM/GPRS/EDGE). OFDMA can be implemented with such a radio technologyas IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, E-UTRA(Evolved UTRA), etc. UTRA is a part of Universal MobileTelecommunications System (UMTS). 3GPP LTE is a part of Evolved UMTS(E-UMTS) that uses E-UTRA. The 3GPP LTE employs OFDMA in DL and SC-FDMAin UL. And, LTE-A is an evolved version of 3GPP LTE.

Moreover, in the following description, specific terminologies areprovided to help the understanding of the present invention. And, theuse of the specific terminology can be modified into another form withinthe scope of the technical idea of the present invention.

FIG. 2 is a block diagram for configurations of a BS 105 and a UE 110 ina wireless communication system 100.

Although one BS 105 and one UE 110 (D2D UE included) are shown in thedrawing to schematically represent the wireless communication system100, the wireless communication system 100 may include at least one BSand/or at least one UE.

Referring to FIG. 2, the BS 105 may include a Transmission (Tx) dataprocessor 115, a symbol modulator 120, a transmitter 125, a transceivingantenna 130, a processor 180, a memory 185, a receiver 190, a symboldemodulator 195 and a received data processor 197. And, the UE 110 mayinclude a Tx data processor 165, a symbol modulator 170, a transmitter175, a transceiving antenna 135, a processor 155, a memory 160, areceiver 140, a symbol demodulator 155 and a received data processor150. Although the BS/UE 105/110 includes one antenna 130/135 in thedrawing, each of the BS 105 and the UE 110 includes a plurality ofantennas. Therefore, each of the BS 105 and the UE 110 of the presentinvention supports a Multiple Input Multiple Output (MIMO) system. And,the BS 105 according to the present invention may support both SingleUser-MIMO (SU-MIMO) and Multi User-MIMO (MU-MIMO) systems.

In DL, the Tx data processor 115 receives traffic data, codes thereceived traffic data by formatting the received traffic data,interleaves the coded traffic data, modulates (or symbol maps) theinterleaved data, and then provides modulated symbols (data symbols).The symbol modulator 120 provides a stream of symbols by receiving andprocessing the data symbols and pilot symbols.

The symbol modulator 120 multiplexes the data and pilot symbols togetherand then transmits the multiplexed symbols to the transmitter 125. Indoing so, each of the transmitted symbols may include the data symbol,the pilot symbol or a signal value of zero. In each symbol duration,pilot symbols may be contiguously transmitted. In doing so, the pilotsymbols may include symbols of Frequency Division Multiplexing (FDM),Orthogonal Frequency Division Multiplexing (OFDM), or Code DivisionMultiplexing (CDM).

The transmitter 125 receives the stream of the symbols, converts thereceived stream to at least one or more analog signals, additionallyadjusts the analog signals (e.g., amplification, filtering, frequencyupconverting), and then generates a downlink signal suitable for atransmission on a radio channel. Subsequently, the downlink signal istransmitted to the user equipment via the antenna 130.

In the configuration of the UE 110, the receiving antenna 135 receivesthe downlink signal from the base station and then provides the receivedsignal to the receiver 140. The receiver 140 adjusts the received signal(e.g., filtering, amplification and frequency downconverting), digitizesthe adjusted signal, and then obtains samples. The symbol demodulator145 demodulates the received pilot symbols and then provides them to theprocessor 155 for channel estimation.

The symbol demodulator 145 receives a frequency response estimated valuefor downlink from the processor 155, performs data demodulation on thereceived data symbols, obtains data symbol estimated values (i.e.,estimated values of the transmitted data symbols), and then provides thedata symbols estimated values to the received (Rx) data processor 150.The received data processor 150 reconstructs the transmitted trafficdata by performing demodulation (i.e., symbol demapping, deinterleavingand decoding) on the data symbol estimated values.

The processing by the symbol demodulator 145 and the processing by thereceived data processor 150 are complementary to the processing by thesymbol modulator 120 and the processing by the Tx data processor 115 inthe BS 105, respectively.

In the UE 110 in UL, the Tx data processor 165 processes the trafficdata and then provides data symbols. The symbol modulator 170 receivesthe data symbols, multiplexes the received data symbols, performsmodulation on the multiplexed symbols, and then provides a stream of thesymbols to the transmitter 175. The transmitter 175 receives the streamof the symbols, processes the received stream, and generates a ULsignal. This UL signal is then transmitted to the BS 105 via the antenna135.

In the BS 105, the UL signal is received from the UE 110 via the antenna130. The receiver 190 processes the received UL signal and then obtainssamples. Subsequently, the symbol demodulator 195 processes the samplesand then provides pilot symbols received in UL and a data symbolestimated value. The received data processor 197 processes the datasymbol estimated value and then reconstructs the traffic datatransmitted from the UE 110.

The processor 155/180 of the user equipment/base station 110/105 directsoperations (e.g., control, adjustment, management, etc.) of the userequipment/base station 110/105. The processor 155/180 may be connectedto the memory unit 160/185 configured to store program codes and data.The memory 160/185 is connected to the processor 155/180 to storeoperating systems, applications and general files.

The processor 155/180 may be called one of a controller, amicrocontroller, a microprocessor, a microcomputer and the like. And,the processor 155/180 may be implemented using hardware, firmware,software and/or any combinations thereof. In the implementation byhardware, the processor 155/180 may be provided with such a deviceconfigured to implement the present invention as Application SpecificIntegrated Circuits (ASICs), Digital Signal Processors (DSPs), DigitalSignal Processing Devices (DSPDs), Programmable Logic Devices (PLDs),Field Programmable Gate Arrays (FPGAs), and the like.

Meanwhile, in case of implementing the embodiments of the presentinvention using firmware or software, the firmware or software may beconfigured to include modules, procedures, and/or functions forperforming the above-explained functions or operations of the presentinvention. And, the firmware or software configured to implement thepresent invention is loaded in the processor 155/180 or saved in thememory 160/185 to be driven by the processor 155/180.

Layers of a radio protocol between a user equipment/base station and awireless communication system (network) may be classified into 1st layerL1, 2nd layer L2 and 3rd layer L3 based on 3 lower layers of Open SystemInterconnection (OSI) model well known to communication systems. Aphysical layer belongs to the 1st layer and provides an informationtransfer service via a physical channel. Radio Resource Control (RRC)layer belongs to the 3rd layer and provides control radio resourcedbetween UE and network. A user equipment and a base station may be ableto exchange RRC messages with each other through a wirelesscommunication network and RRC layers.

In the present specification, although the processor 155/180 of the userequipment/base station performs an operation of processing signals anddata except a function for the user equipment/base station 110/105 toreceive or transmit a signal, for clarity, the processors 155 and 180will not be mentioned in the following description specifically. In thefollowing description, the processor 155/180 can be regarded asperforming a series of operations such as a data processing and the likeexcept a function of receiving or transmitting a signal without beingspecially mentioned.

FIG. 3 is a view illustrating exemplary radio frame structures in a 3GPPLTE/LTE-A system as an exemplary wireless communication system.

In general, regarding wireless transmission between a BS and a UE whichare wireless devices, transmission from the BS to the UE is genericallycalled DL transmission, and transmission from the UE to the BS isgenerically called UL transmission. A scheme of distinguishing radioresources between DL transmission and UL transmission is defined asduplex. If a frequency band is divided into a DL transmission band and aUL transmission band, and bidirectional transmission and reception areperformed in the DL and UL transmission bands, this is referred to asFrequency Division Duplex (FDD). On the other hand, if time-domain radioresources in the same frequency band are divided into a DL period and aUL period and transmission and reception are performed in the DL and ULperiods, this is referred to as Time Division Duplex (TDD).

In a cellular OFDM wireless packet communication system, UL/DL datapackets are transmitted in subframes, and one subframe is defined as apredetermined time period including a plurality of OFDM symbols. The3GPP LTE standards support a type-1 radio frame structure applicable toFDD and a type-2 radio frame structure applicable to TDD.

FIG. 3(a) illustrates the structure of the type 1 radio frame. A DLradio frame includes 10 subframes, each subframe including two slots inthe time domain. A time taken to transmit one subframe is defined as aTransmission Time Interval (TTI). For example, one subframe may be lmslong, and one slot may be 0.5 ms long. One slot includes a plurality ofOFDM symbols in time by a plurality of Resource Blocks (RBs) infrequency. Since the 3GPP LTE system adopts OFDMA for DL, an OFDM symbolis one symbol period. An OFDM symbol may also be referred to as anSC-FDMA symbol or symbol period. An RB being a resource allocation unitmay include a plurality of contiguous subcarriers in one slot.

The number of OFDM symbols in one slot may be different according to aCyclic Prefix (CP) configuration. There are two types of CPs, normal CPand extended CP. For example, if an OFDM symbol is configured to includea normal CP, one slot may include seven OFDM symbols. On the other hand,if an OFDM symbol is configured to include an extended CP, the length ofone OFDM symbol is increased and thus one slot includes fewer OFDMsymbols than in the case of the normal CP. In the case of the extendedCP, for example, one slot may include six OFDM symbols. If a channelstate is unstable as is the case with a fast moving UE, the extended CPmay be used to further reduce inter-symbol interference.

In the case of the normal CP, one slot includes seven OFDM symbols, andthus one subframe includes 14 OFDM symbols. Up to three first OFDMsymbols of each subframe may be allocated to a Physical Downlink ControlChannel (PDCCH), and the other OFDM symbols of the subframe may beallocated to a Physical Downlink Shared Channel (PDSCH).

FIG. 3(b) illustrates the structure of the type 2 radio frame.

A type 2 radio frame includes two half frames, each half frame includingfive subframes, a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP),and an Uplink Pilot Time Slot (UpPTS). A subframe includes two slots.The DwPTS is used for initial cell search, synchronization, or channelestimation at a UE. The UpPTS is used for an eNB to perform channelestimation and acquire UL synchronization with a UE. The GP is used tocancel UL interference between a UL and a DL, caused by the multi-pathdelay of a DL signal.

Each half frame includes five subframes, D represents a DL subframe, Urepresents a UL subframe, and S represents a special subframe includinga DwPTS, a GP, and a UpPTS. The DwPTS is used for initial cell search,synchronization, or channel estimation at a UE. The UpPTS is used for aneNB to perform channel estimation and acquire UL synchronization with aUE. The GP is used to cancel UL interference between a UL and a DL,caused by the multi-path delay of a DL signal.

In the case of a 5-ms DL-UL switch point periodicity, a special subframeS exists in every half frame. Subframe 0 and subframe 5, and DwPTSs areused for DL transmission only. A UpPTS and a subframe shortly followinga special subframe are used for UL transmission only. If multiple cellsare aggregated, a UE may assume the same UL-DL configuration across allcells, and the GP of a special subframe may overlap over at least 1456Tsbetween different cells. The radio frame structures are purelyexemplary, and thus the number of subframes in a radio frame, the numberof slots in a subframe, and the number of symbols in a slot may bechanged in various manners.

FIG. 4 illustrates a resource grid for the duration of one DL slot inthe 3GPP LTE/LTE-A system as an exemplary wireless communication system.

Referring to FIG. 4, a DL slot includes a plurality of OFDM symbols inthe time domain. One DL slot includes 7 (or 6) OFDM symbols in the timedomain by a plurality of Resource Blocks (RBs) in the frequency domain.Each RB includes 12 subcarriers. Each element of a resource grid iscalled a Resource Element (RE). One RB includes 12×7(6) REs. The numberof RBs in a DL slot, N_(RB) depends on a DL transmission band. Thestructure of a UL slot is identical to that of a DL slot, except thatOFDM symbols are replaced with SC-FDMA symbols.

FIG. 5 is a view illustrating an exemplary UL subframe structure in the3GPP LTE/LTE-A system as an exemplary wireless communication system.

Referring to FIG. 5, up to three (or four) OFDM symbols at the start ofthe first slot of a subframe corresponds to a control region to which acontrol channel is allocated. The other OFDM symbols of the subframecorrespond to a data region to which a PDSCH is allocated. DL controlchannels used in 3GPP LTE include a Physical Control Format IndicatorChannel (PCFICH), a Physical Downlink Control Channel (PDCCH), and aPhysical Hybrid Automatic Repeat reQuest (HARQ) Indicator Channel(PHICH). The PCFICH is transmitted in the first OFDM symbol of asubframe, carrying information about the number of OFDM symbols used fortransmission of control channels in the subframe. The PHICH carries aHARQ ACK/NACK signal in response to a UL transmission.

Control information carried on the PDCCH is called Downlink ControlInformation (DCI). DCI format 0 is defined for UL scheduling, and DCIformats 1, 1A, 1B, 1C, 1D, 2, 2A, 3, and 3A are defined for DLscheduling. Depending on its usage, a DCI format selectively includesinformation such as a hopping flag, an RB assignment, a ModulationCoding Scheme (MCS), a Redundancy Version (RV), a New Data Indicator(NDI), a Transmit Power Control (TPC), a cyclic shift, a DeModulationReference Signal (DM RS), a Channel Quality Information (CQI) request,an HARQ process number, a Transmitted Precoding Matrix Indicator (TPMI),Precoding Matrix Indicator (PMI) confirmation, and so on.

The PDCCH delivers a transport format and resource allocationinformation for a Downlink Shared Channel (DL-SCH), a transport formatand resource allocation information for an Uplink Shared Channel(UL-SCH), paging information of a Paging Channel (PCH), systeminformation on the DL-SCH, information about resource allocation for ahigher-layer control message such as a random access responsetransmitted on the PDSCH, a set of Tx power control commands forindividual UEs of a UE group, a TPC command, Voice Over InternetProtocol (VoIP) activation indication information, and so on. Aplurality of PDCCHs may be transmitted in the control region. A UE maymonitor a plurality of PDCCHs. A PDCCH is transmitted in an aggregate ofone or more consecutive Control Channel Elements (CCEs). A CCE is alogical allocation unit used to provide a PDCCH at a coding rate basedon the state of a radio channel. A CCE includes a plurality of REGs. Theformat of a PDCCH and the number of bits in the PDCCH are determinedaccording to the number of CCEs. An eNB determines a PDCCH formataccording to control information to be transmitted to a UE and adds aCyclic Redundancy Check (CRC) to the control information. The CRC ismasked by an Identifier (ID) (e.g., a Radio Network Temporary Identifier(RNTI)) according to the owner or usage of a PDCCH. If the PDCCH isdirected to a specific UE, its CRC may be masked with a Cell-RNTI(C-RNTI) of the UE. If the PDCCH is for a paging message, the CRC of thePDCCH may be masked with a Paging Radio Network Temporary Identifier(P-RNTI). If the PDCCH delivers system information (more specifically, aSystem Information Block (SIB)), the CRC may be masked with a SystemInformation RNTI (SI-RNTI). If the PDCCH is for a random accessresponse, the CRC may be masked with a Random Access-RNTI (RA-RNTI).

FIG. 6 is a view illustrating an exemplary DL subframe structure in the3GPP LTE/LTE-A system as an exemplary wireless communication system.

Referring to FIG. 6, a UL subframe includes a plurality of (two) slots.A slot may include a different number of SC-FDMA symbols according to aCP length. The UL subframe may be divided into a control region and adata region in the frequency domain. A Physical Uplink Shared Channel(PUSCH) carrying user data such as voice is allocated to the dataregion. A Physical Uplink Control Channel (PUCCH) carrying UplinkControl Information (UCI) is allocated to the control region. The PUCCHincludes an RB pair located at both ends of the data region along thefrequency axis and hops over a slot boundary.

The PUCCH may carry the following control information.

-   -   Scheduling Request (SR): information used to request UL-SCH        resources. The SR is transmitted in On-Off Keying (OOK).    -   HARQ ACK/NACK: a response signal to a DL data packet on a PDSCH.        The HARQ ACK/NACK indicates whether the DL data packet has been        received successfully. A 1-bit ACK/NACK is transmitted as a        response to a single DL CodeWord (CW) and a 2-bit ACK/NACK is        transmitted as a response to two DL CWs.    -   Channel Quality Indicator (CQI): feedback information for a DL        channel. MIMO-related feedback information includes an RI, a        PMI, a PTI, and so on. The CQI occupies 20 bits per subframe.

The amount of UCI that a UE may transmit in a subframe depends on thenumber of SC-FDMA symbols available for transmission of the UCI. TheSC-FDMA symbols available for transmission of the UCI are the remainingSC-FDMA symbols except for SC-FDMA symbols configured for transmittingRSs in the subframe. The last SC-FDMA symbol of a subframe configured tocarry an SRS is additionally excluded from the SC-FDMA symbols availablefor transmission of the UCI. An RS is used for coherent detection of aPUCCH. A PUCCH supports 7 formats according to information carried onthe PUCCH.

An FDR system in which UL and DL signals can be transmitted and receivedsimultaneously in the same frequency band has attracted much interest asone of the core technologies of a future 5th Generation (5G) mobilecommunication system, because it doubles spectral efficiency at maximum,compared to a legacy system in which UL and DL signals are transmittedand received in frequency division or time division.

FDR may be defined as a transmission resource configuration scheme ofsimultaneously performing transmission and reception in a singletransmission frequency band, from the viewpoint of a wireless device. Aspecial example of FDR may be a transmission resource configurationscheme in which a general BS (relay, relay node, or Remote Radio Head(RRH)) simultaneously performs DL transmission and UL reception and a UEsimultaneously performs DL reception and UL transmission, in a singlefrequency transmission band during communication between the BS and theUE. In another example, FDR may be a transmission resource configurationscheme in which transmission and reception take place in the sametransmission frequency band between UEs during Device to Device (D2D)communication between the UEs. While the following description is givenof proposed FDR-related techniques in the context of wirelesstransmission and reception between a general BS and a UE, it also coverswireless communication between a wireless network other than a generalBS and a UE, and D2D communication between UEs.

FIG. 7 is a conceptual view of Transmission (Tx) and Reception (Rx)links and Self-Interference (SI) in an FDM communication situation.

Referring to FIG. 7, there are two types of SI, direct interferencecaused by a signal transmitted through a Tx antenna of a BS or UE andthen received at an Rx antenna of the BS or UE, and reflectedinterference caused by a signal reflected from adjacent topography. Dueto a physical distance difference, the magnitude of SI is extremelylarge, compared to a desired signal. That's why it is necessary toeffectively cancel SI, for implementation of an FDR system.

To effectively operate the FDR system, Self-IC requirements with respectto the maximum transmission power of devices (in the case where FDR isapplied to a mobile communication system (BW=20 MHz)) may be determinedas illustrated in [Table 1] below.

TABLE 1 Max. Tx Power Thermal Noise. Receiver Thermal Self-IC TargetNode Type (P_(A)) (BW = 20 MHz) Receiver NF Noise Level (P_(A)- TN-NF)Macro eNB 46 dBm −101 dBm 5 dB (for eNB) −96 dBm 142 dB Pico eNB 30 dBm126 dB Femto eNB, 23 dBm 119 dB WLAN AP UE 23 dBm 9 dB (for UE)  −92 dBm115 dB

Referring to [Table 1], it may be noted that to effectively operate theFDR system in a 20-MHz BW, a UE needs 119-dBm Self-IC performance. Athermal noise value may be changed to N_(0,BW)=−174 dBm+10×log₁₀ (BW)according to the BW of a mobile communication system. In [Table 1], thethermal noise value is calculated on the assumption of a 20-MHz BW. Inrelation to [Table 1], for Receiver Noise Figure (NF), a worst case isconsidered referring to the 3GPP specification requirements. ReceiverThermal Noise Level is determined to be the sum of a thermal noise valueand a receiver NF in a specific BW.

Types of Self-IC Schemes and Methods for Applying the Self-IC Schemes

FIG. 8 is a view illustrating positions at which three Self-IC schemesare applied, in a Radio Frequency (RF) Tx and Rx end (or an RF frontend) of a device. Now, a brief description will be given of the threeSelf-IC schemes.

Antenna Self-IC:

Antenna Self-IC is a Self-IC scheme that should be performed first ofall Self-IC schemes. SI is cancelled at an antenna end. Most simply,transfer of an SI signal may be blocked physically by placing asignal-blocking object between a Tx antenna and an Rx antenna, thedistance between antennas may be controlled artificially, using multipleantennas, or a part of an SI signal may be canceled through phaseinversion of a specific Tx signal. Further, a part of an SI signal maybe cancelled by means of multiple polarized antennas or directionalantennas.

Analog Self-IC:

Interference is canceled at an analog end before an Rx signal passesthrough an Analog-to-Digital Convertor (ADC). An SI signal is canceledusing a duplicated analog signal. This operation may be performed in anRF region or an Intermediate Frequency (IF) region. SI signalcancellation may be performed in the following specific method. Aduplicate of an actually received SI signal is generated by delaying ananalog Tx signal and controlling the amplitude and phase of the delayedTx signal, and subtracted from a signal received at an Rx antenna.However, due to the analog signal-based processing, the resultingimplementation complexity and circuit characteristics may causeadditional distortion, thereby changing interference cancellationperformance significantly.

Digital Self-IC:

Interference is canceled after an Rx signal passes through an ADC.Digital Self-IC covers all IC techniques performed in a baseband region.Most simply, a duplicate of an SI signal is generated using a digital Txsignal and subtracted from an Rx digital signal. Or techniques ofperforming precoding/postcoding in a baseband using multiple antennas sothat a Tx signal of a UE or an eNB may not be received at an Rx antennamay be classified into digital Self-IC. However, since digital Self-ICis viable only when a digital modulated signal is quantized to a levelenough to recover information of a desired signal, there is a need forthe prerequisite that the difference between the signal powers of adesigned signal and an interference signal remaining after interferencecancellation in one of the above-described techniques should fall intoan ADC range, to perform digital Self-IC.

FIG. 9 is a block diagram of a Self-IC device in a proposedcommunication apparatus in an OFDM communication environment based onFIG. 8.

While FIG. 9 shows that digital Self-IC is performed using digital SIinformation before Digital to Analog Conversion (DAC) and after ADC, itmay be performed using a digital SI signal after Inverse Fast FourierTransform (IFFT) and before Fast Fourier Transform (FFT). Further,although FIG. 9 is a conceptual view of Self-IC though separation of aTx antenna from an Rx antenna, if antenna Self-IC is performed using asingle antenna, the antenna may be configured in a different manner fromin FIG. 9. A functional block may be added to or removed from an RF Txend and an RF Rx end shown in FIG. 9 according to a purpose.

Signal Modeling in FDR System

Because an FDR system uses the same frequency for a Tx signal and an Rxsignal, non-linear components of an RF end affect the FDR systemsignificantly. Especially, a Tx signal is distorted by an active devicesuch as a Power Amplifier (PA) and a Low Noise Amplifier (LNA), and thedistortion may be modeled as generation of high-order components of a Txsignal. Among the high-order components, an even-order component can beremoved effectively by conventional Alternate Coupling (AC) coupling orfiltering because the even-order component affects the vicinity of DC.Compared to the even-order component, an odd-order component is noteasily removed and has a great influence, because the odd-ordercomponent is produced in the vicinity of an existing frequency. Inconsideration of the non-linearity of the odd-order component, an Rxsignal after ADC in the FDR system may be represented as [Equation 1]using a Parallel Hammerstain (PH) Model.

$\begin{matrix}{{y(n)} = {{{h_{D}(n)}*{x_{D}(n)}} + {\sum\limits_{\underset{k = {odd}}{{k = 1},\ldots \;,K}}\; {{h_{{SI},k}(n)}*{{x_{SI}(n)}}^{k - 1}{x_{SI}(n)}}} + {z(n)}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

where x_(D)(n) represents desired data to be received, h_(D)(n)represents a desired channel that the desired data experiences, andx_(S1)(n) represents self-transmitted data. h_(S1,k)(n) represents an SIchannel that the self-transmitted data experiences. If k is 1, thisindicates a linear component, and if k is an odd value equal to or largethan 3 indicate a non-linear component. Further, z(n) representsAdditive White Gaussian Noise (AWGN).

Need for Non-Linear Self-IC Scheme

To effectively Self-IC of FDR, a non-linear SI channel is required.However, Least Square (LS) estimation used to estimate an SI channelrequires matrix inversion. The matrix inversion needs high-complexitycomputation, and an implementation problem occurs during the matrixinversion according to a matrix size. More specifically, if a non-linearorder or the number of multi-path taps, which should be estimated forFDR operation, increases, the size of a matrix to be inverted increases,and the complexity of the matrix inversion also increases to a matrixsize to the third power. Thus, the matrix inversion is impossible toperform.

To overcome the high complexity and implementation impossibility ofnon-linear SI channel estimation, use of a sequence for non-linear SIchannel estimation may be considered. More specifically, a high-ordercomponent of an SI channel modeled by [Equation 1] may be estimated withlow complexity, using the cross-correlation property of a sequence, andthis method can be implemented simply, relative to a matrix version.Also, a scheme of estimating a multi-path component corresponding toeach order as well as a high-order component of an SI channel, using theautocorrelation and cross correlation properties of a sequence ispossible. This scheme may also enable low-complexity SI estimation. Evenwhen a non-linear order and the number of multi-path taps to beestimated for FDR operation are increased, complexity increases linearlyin these schemes. Thus, complexity is reduced remarkably andimplementation is also possible.

Nonetheless, even though non-linear SI estimation and cancellation ispossible with low complexity, as described above, the non-linear SIestimation is still burdensome in terms of insufficient computing powerof a UE. Accordingly, there is a need for a scheme of relieving theconstraint of Self-IC by controlling the amount of non-linear SI at asystem level.

Need for Operating FDR on Subband Basis

Self-IC techniques developed so far are based on FDR operation across atotal band. For real FDR implementation, however, it is necessary to usea partial band in FDR according to asymmetric DL/UL data traffic of eachUE, instead of a total band. If DL/UL data traffic is constant at eachFDR operation, the above scheme is viable. However, it is typical thatthe ratio between DL traffic and UL traffic is different, andparticularly, there are more DL data traffic than UL data traffic for aUE due to asymmetric DL/UL data traffic. Therefore, it may be efficientfor a UE to operate in FDR on a subband basis. That's why per-subbandFDR operation is essential during system development.

Overhead of Non-linear SI Channel Estimation

When RSs are configured for channel estimation in the legacy LTE system,Common RSs or Cell-specific RSs (CRSs), Channel State Information-RSs(CSI-RSs), DeModulation RSs (DMRS), and so on are positioned with apredetermined spacing between them in the time and frequency domains.Then, channel estimation may be performed by various One-Dimensional(1D) or Two-Dimensional (2D) interpolation schemes (block interpolation,linear interpolation, non-linear interpolation, and so on) usingdemodulated RSs. However, a non-linear component called Inter-ModulationDistortion (IMD) is included in an SI signal in view of thenon-linearity of a device in the FDR system. Therefore, if theconventional interpolation schemes are used, IMD components are notreflected, thereby making non-linear SI channel estimation impossible.In this context, there is a need for a non-linear SI channel estimationscheme that considers non-linearity.

In the FDR system, IMD has the following effects. Above all, IMD isproduced due to the non-linearity of a device, meaning that an odd termcomponent among high-order components of a Tx signal is generated in thevicinity of the Tx signal.

FIG. 10 is a view illustrating exemplary 3^(rd) IMD components generatedin adjacent frequency bands during two-tone transmission.

Referring to FIG. 10, 3 rd IMD components generated during transmissionof two tones at 1900 MHz and 1900.1 MHz with a spacing of 1 KHz in anOFDM signal are shown empirically. It is noted from FIG. 10 that IMDoccurs at 18999.9 MHz and 19000.2 MHz apart from both ends of thetransmitted two tones (or RSs) by the frequency difference between thetwo tones during the two-tone transmission. Based on the resultillustrated in FIG. 10, IMD generated during multi-tone transmission ofan OFDM signal is illustrated in FIGS. 11 and 12.

FIG. 11 is a view illustrating exemplary 3^(rd) IMD components generatedduring multi-tone transmission, and FIG. 12 is a graph illustratingpower spectral densities (dB) including IMD components in an OFDMsystem.

Referring to FIGS. 11 and 12, in the case of multi-tone transmission,the number of generated IMD components increases exponentially accordingto the number and spacing of transmitted tones. Therefore, modeling ofmultiple tones in the frequency domain is complex because IMD componentsgenerated by each tone should be measured and modeled.

For example, if a signal is transmitted in a 20-MHz BW in conformance tothe 3GPP LTE standards, a total of 1200 OFDM subcarriers aretransmitted, and 719400 (1200×1199/2) IMD components are generated.Modeling of the IMD components in the frequency domain is complex, andit is impossible to estimate each IMD component in the frequency domain.Accordingly, to estimate a non-linear SI channel in the FDR system, itis necessary to model and estimate the SI channel in the time domain. RSoperation in the time domain increases RS overhead.

Power of IMD Component of SI Caused by Non-Linearity of PA

FIG. 13 is a view comparing the power amounts of IMD components atrespective tones according to transmission BWs.

As described before, IMD components are included in SI caused by thenon-linearity of a PA. The power of the IMD components is proportionalto the number of IMD components in each tone. More specifically, FIG. 13illustrates that the number of IMD components varies with the number oftransmitted tones (a subcarrier spacing between tones is maintained).

It may be noted from FIG. 13 that as a Tx BW increases, the number ofIMD components generated at the position of each tone also increases.The relative power of IMD components whose number increases with the BWis given as [Equation 2].

$\begin{matrix}{{D_{IMD}(f)} = {\frac{1}{2}\left\{ {{A_{D}\left( f_{k} \right)}\left( \frac{{e\eta}_{PD}}{hv} \right)P_{r}} \right\}^{2}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

where A_(D)(f_(K)) represents the amplitude of an IMD componentgenerated at the position of a tone f_(K), e represents electron charge,η_(PD) represents Photo Detection (PD) efficiency, h represents aPlanck's constant, v represents a center frequency, and Pr representsinput power.

$\begin{matrix}{{A_{D}\left( f_{k} \right)} = {{\frac{3}{4}a_{3}m_{k}^{3}{N_{D_{2}}\left( f_{k} \right)}} + {\frac{3}{2}a_{3}m_{k}^{3}{N_{D_{23}}\left( f_{k} \right)}}}} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

where N_(D2)(f_(K)) and N_(D3)(f_(K)) represent the numbers of IMDcomponents generated during two-tone transmission and three-tonetransmission, respectively.

As noted from [Equation 2] and [Equation 3], as a BW increases, theresulting increase in the number of IMD components of SI leads to apower increase, and the power increment is proportional to the square ofthe increase of the number of IMD components.

Hereinbelow, the present invention proposes schemes of effectivelyapplying FDR to wireless transmission between a BS and a UE. The term BSas used across the present specification may cover relay, relay node,RRH, and so on. The present invention proposes resource structuressuitable for FDR wireless transmission and related resource mappingmethods.

Proposal 1: A PRB mapping rule is established in such a manner that RBGsmay be configured by distributing PRBs non-uniformly in order to reduce3rd IMD.

In the LTE system, an RBG unit varies with a system BW. For theconvenience of description, the following description will be given withthe appreciation that RBG=4 in the present invention. However, thepresent invention is not limited to RBG=4, and in other cases, forexample, in the case where an RBG includes any other number of RBs as inRBG=2, 3, 4, or 6, the present invention is applicable with a slightmodification to an algorithm.

As described before, the power of IMD components of SI caused by thenon-linearity of a PA is related to a Tx BW, and PRB mapping of an RBGmay be changed as follows to reduce 3^(rd) IMD as in Proposal 1.

A legacy UE (e.g., a UE operating in half-duplex mode) that does notsupport FDR configures RBGs by sequentially grouping contiguous PRBs inthe frequency domain in a conventional localized RBG configurationscheme as defined in 3GPP TS 36.211 6.2.4 Resource-element groups. Theresulting SI signal and IMD components of the SI signal are shown inFIG. 14.

FIG. 14 is a view illustrating linear and non-linear SI components ateach tone in a conventional RBG configuration rule.

Referring to FIG. 14, linear SI components exist with respect to PRBs#4, #5, #6, and #7, and non-linear SI components, IMD caused by eachtone interfere with adjacent PRBs. On the other hand, a Tx BW is reducedand IMD components of each tone may be reduced by separating contiguousPRBs non-uniformly, as illustrated in FIG. 15.

FIG. 15 is a view illustrating linear and non-linear SI components ateach tone, when RBGs are configured non-uniformly.

Referring to FIG. 15, linear SI components exist with respect to PRBs#1, #3, #8, and #10, and non-linear SI components, IMD caused by eachtone spread even to adjacent PRBs. The total power of a linear SI signalcomponent and a non-linear SI component is equal in the two schemes (theconventional RBG configuration rule, and the non-uniform RBGconfiguration scheme). However, the power value of IMD generated at eachtone differs. That is, it is obvious that IMD power of each tonegenerated in a proposed RBG is less than IMD power of each tonegenerated in a conventional RBG. Since PRBs are configurednon-uniformly, IMD components may also spread to the positions of aplurality of tones and, as a result, the number of IMD componentsgenerated at each tone may be reduced. Accordingly, the IMD power valueof each tone may be decreased.

Embodiment 1-1

FIG. 16A is a view illustrating an exemplary method for configuring RBGsby grouping 16 contiguous Physical Resource Blocks (PRBs) for RBG=4according to a first proposal (Proposal 1) of the present invention, andFIG. 16B illustrates an exemplary PRB mapping table laid out accordingto FIG. 16A.

FIG. 16A also describes a general formula for generating RBGs bygrouping 16 contiguous PRBs. For RBG=4, to configure RBGs bydistributing PRBs non-uniformly, RBGs may be configured by grouping eachset of PRBs #0, #2, #8, and #10, PRBs #1, #3, #9, and #11, PRBs #4, #6,#12, and #14, and PRBs #5, #7, #13, and #15 into one RBG.

As illustrated in FIG. 16B, PRB indexes may be mapped to RBG indexes insuch a manner that PRBs #0, #2, #8, and #10 are mapped to RBG index 0,PRBs #1, #3, #9, and #11 are mapped to RBG index 1, PRBs #4, #6, #12,and #14 are mapped to RBG index 2, and PRBs #5, #7, #13, and #15 aremapped to RBG index 3.

Embodiment 1-2

FIG. 17A is a view illustrating an exemplary method for configuring RBGsby grouping 12 contiguous PRBs for RBG=4 according to Proposal 1 of thepresent invention, and FIG. 17B illustrates an exemplary PRB mappingtable laid out according to FIG. 17A.

Referring to FIG. 17A, for RBG=4, RBGs may be configured by grouping 12contiguous PRBs in Proposal 1. To configure RBGs by distributing PRBsnon-uniformly for RBG=4, RBGs may be configured by grouping each set ofPRBs #0, #2, #5, and #7, PRBs #1, #3, #8, and #10, and PRBs #4, #6, #9,and #11 into one RBG.

As illustrated in FIG. 17B, PRB indexes may be mapped to RBG indexes insuch a manner that PRBs #0, #2, #5, and #7 are mapped to RBG index 0,PRBs #1, #3, #8, and #10 are mapped to RBG index 1, and PRBs #4, #6, #9,and #11 are mapped to RBG index 2.

Embodiment 1-3

FIG. 18A is a view illustrating an exemplary method for configuring RBGsby grouping 64 contiguous PRBs for RBG=4 according to a Proposal 1 ofthe present invention, and FIG. 18B illustrates an exemplary PRB mappingtable laid out according to FIG. 18A.

FIG. 18A also describes a general formula for generating RBGs bygrouping 64 contiguous PRBs. To configure RBGs by distributing PRBsnon-uniformly for RBG=4, RBGs may be configured by grouping each set ofPRBs #0, #8, #35, and #43, PRBs #1, #9, #34, and #42, PRBs #2, #10, #33,and #41, and PRBs #3, #11, #32, and #40 into one RBG.

As illustrated in FIG. 18B, PRB indexes may be mapped to RBG indexes insuch a manner that PRBs #0, #8, #35, and #43 are mapped to RBG index 0,PRBs #1, #9, #34, and #42 are mapped to RBG index 1, PRBs #2, #10, #33,and #41 are mapped to RBG index 2, and PRBs #3, #11, #32, and #40 aremapped to RBG index 3.

Embodiment 1-4

FIG. 19A is a view illustrating an exemplary method for configuring RBGsby grouping 48 contiguous PRBs for RBG=4 according to a Proposal 1 ofthe present invention, and FIG. 19B illustrates an exemplary PRB mappingtable laid out according to FIG. 19A.

FIG. 19A also describes a general formula for generating RBGs bygrouping 48 contiguous PRBs. To configure RBGs by distributing PRBsnon-uniformly for RBG=4, RBGs may be configured by grouping each set ofPRBs #0, #8, #35, and #43, PRBs #1, #9, #34, and #42, PRBs #2, #10, #33,and #41, and PRBs #3, #11, #32, and #40 into one RBG.

As illustrated in FIG. 19B, PRB indexes may be mapped to RBG indexes insuch a manner that PRBs #0, #8, #35, and #43 are mapped to RBG index 0,PRBs #1, #9, #34, and #42 are mapped to RBG index 1, PRBs #2, #10, #33,and #41 are mapped to RBG index 2, and PRBs #3, #11, #32, and #40 aremapped to RBG index 3.

The above examples illustrate PRB mapping results for RBG=4. However, asdescribed before, even though an RBG is configured to include adifferent number of PRBs or in a different size, PRBs may be groupednon-uniformly in consideration of IMD components, thereby reducing IMD.

Proposal 2: If each RBG includes three or fewer PRBs, PRB mapping may beperformed using a subset of a set of 4 PRBs or in a new PRB mappingrule.

For RBGs each including three or fewer PRBs (RBG=2 or 3), PRBs may bemapped in the following embodiments based on the foregoing embodimentsin which each RBG includes four PRBs. For RBG=2, PRB mapping may beperformed by selecting a part of the embodiments of Proposal 1, and forRBG=3, resources may be allocated according to a new PRB mapping rule inorder to increase a resource use rate.

Embodiment 2-1

For RBG=2, PRB mapping may be performed by selecting two PRBs out offour PRBs in Embodiment 1-1, Embodiment 1-2, Embodiment 1-3, andEmbodiment 1-4 according to Proposal 2.

If two PRBs are selected out of four PRBs grouped into one RBG inEmbodiment 1-1, Embodiment 1-2, Embodiment 1-3, and Embodiment 1-4, atotal of six methods (PRBs #1 and #2, PRBs #1 and #3, PRBs #1 and #4,PRBs #2 and #3, PRBs #2 and #4, and PRBs #3 and #4) are available.However, it is preferred to select PRBs #1 and #2 in a pair as follows,in consideration of efficiency of PRB resources and IMD effects.

FIG. 20A is a view illustrating an exemplary PRB mapping of two PRBsselected from among four PRBs for RBG=2 in Embodiment 1-1, Embodiment1-2, Embodiment 1-3, and Embodiment 1-4 according to a second proposal(Proposal 2) of the present invention, and FIG. 20B is an exemplary PRBmapping table laid out according to FIG. 20A.

FIG. 20A also describes a general formula for generating RBGs bygrouping 12 contiguous PRBs. To configure RBGs by distributing PRBsnon-uniformly for RBG=2, each pair of PRBs #0 and #2, PRBs #1 and #3,PRBs #4 and #6, PRBs #5 and #7, PRBs #8 and #10, and PRBs #9 and #11 maybe grouped into one RBG.

Referring to FIG. 20B, PRB indexes may be mapped to RBG indexes in sucha manner that PRBs #0 and #2 are mapped to RBG index 0, PRBs #1 and #3are mapped to RBG index 1, PRBs #4 and #6 are mapped to RBG index 2,PRBs #5 and #7 are mapped to RBG index 3, PRBs #8 and #10 are mapped toRBG index 4, and PRBs #9 and #11 are mapped to RBG index 5.

Apart from Embodiment 2-1, the remaining five combinations (PRB #1/#3,PRB #1#4, PRB #2#3, PRB #2#4, PRB #3#4) out of the six combinations arealso available.

Embodiment 2-2

For RBG=3, PRB mapping may be performed by selecting three PRBs out offour PRBs grouped into each RBG in Embodiment 1-1, Embodiment 1-2,Embodiment 1-3, and Embodiment 1-4.

As described above, a total of four methods (PRBs #1, #2, and #3, PRBs#1, #2, and #4, PRBs #1, #3, and #4, PRBs #2, #3, and #4) are availableto perform PRB mapping by selecting three PRBs out of four PRBs groupedinto each RBG in Embodiment 1-1, Embodiment 1-2, Embodiment 1-3, andEmbodiment 1-4.

Embodiment 2-3

For RBG=3, a new PRB mapping rule may be established in order toincrease the efficiency of resources of Embodiment 2-2.

FIG. 21A is a view illustrating an exemplary method for configuring RBGsby grouping 12 contiguous PRBs for RBG=3 according to Proposal 2 of thepresent invention, and FIG. 21B illustrates an exemplary PRB mappingtable laid out according to FIG. 21A.

FIG. 21A also describes a general formula for generating RBGs bygrouping 12 contiguous PRBs. To configure RBGs by distributing PRBsnon-uniformly for RBG=3, each set of PRBs #0, #2, and #5, PRBs #1, #3,and #7, PRBs #4, #8 and #10, and PRBs #6, #9 and #11 may be grouped intoone RBG.

Referring to FIG. 21B, PRB indexes may be mapped to RBG indexes in sucha manner that PRBs #0, #2, and #5 are mapped to RBG index 0, PRBs #1,#3, and #7 are mapped to RBG index 1, PRBs #4, #8 and #10 are mapped toRBG index 2, and PRBs #6, #9 and #11 are mapped to RBG index 3.

Proposal 3: A PRB mapping rule is established so that RBGs areconfigured by grouping every n PRBs (subgroup PRB=n) into one RBG inorder to reduce 3^(rd) IMD.

In Proposal 1, IMD is determined by separating every PRB non-uniformly.However, if the number of RBGs increases, non-uniform distributed PRBmapping like Proposal 1 is not easy. Moreover, even though PRBs may bedistributed non-uniformly, there may exist non-mapped PRBs. To preventthe presence of non-mapped PRBs, a PRB mapping rule may be establishedby setting subgroup PRB=n by grouping every n PRBs into one RBG and thusdistributing PRBs non-uniformly on a subgroup basis.

Embodiment 3-1

For RBG=6, RBGs may be configured by grouping 24 contiguous PRBs withsubgroup PRB=2 according to Proposal 2.

FIG. 22A is a view illustrating an exemplary method for configuring RBGsby grouping 24 contiguous PRBs for RBG=6 according to a third proposal(Proposal 3) of the present invention, and FIG. 22B is an exemplary PRBmapping table laid out according to FIG. 22A.

FIG. 22A also describes a general formula for generating RBGs bygrouping 12 contiguous PRBs with subgroup PRB=2 (subgroups each havingtwo PRBs are configured).

To configure RBGs by distributing PRBs non-uniformly for RBG=6, each setof PRBs #0, #1, #4, #5, #14, and #15, PRBs #2, #3, #12, #13, #16, and#17, PRBs #6, #7, #10, #11, #20, and #21, and PRBs #8, #9, #18, #19, #22and #23 may be grouped into one RBG.

Referring to FIG. 22B, PRB indexes may be mapped to RBG indexes in sucha manner that PRBs #0, #1, #4, #5, #14, and #15 are mapped to RBG index0, PRBs #2, #3, #12, #13, #16, and #17 are mapped to RBG index 1, PRBs#6, #7, #10, #11, #20, and #21 are mapped to RBG index 2, and PRBs #8,#9, #18, #19, #22 and #23 are mapped to RBG index 3.

Embodiment 3-1 illustrates PRB mapping results for RBG=6. However, asdescribed before, even though an RBG is configured to include adifferent number of PRBs or in a different size, a plurality of subgroupPRBs may be grouped non-uniformly in consideration of IMD components,thereby reducing IMD.

According to Proposal 1, Proposal 2, and Proposal 3, if an eNB indicatesRBG indexes to a UE by DCI/UCI, the UE may determine PRB indexes mappedto the RBG indexes, referring to a PRB mapping table that maps PRBindexes to RBG indexes, and thus determine resource allocation positionsfor PDSCH reception and resource allocation positions for PUCCH/PUSCHtransmission. The RBG indexes may be signaled in a bitmap.

Proposal 4: An RB gap value may be configured for distributed resourceallocation in Proposal 1.

As defined in 3GPP TS 36.213 Table 7.1.6.1-1, RBG sizes are setaccording to system BWs (the number of DL RBs should be a multiple of anRBG size for a corresponding system BW).

[Table 2] lists type 0 resource allocation RBG sizes for DL system BWsin 3GPP TS 36.213 Table 7.1.6.1-1.

TABLE 2 System Bandwidth N_(RB) ^(DL) RBG Size (P′) ≤10 1 11-26 2 27-633  64-110 4

As defined in 3GPP TS 36.211 6.2.3.2-1, RB gap values are set for systemBWs, for distributed resource allocation.

Table 3

TABLE 3 System BW Gap (N_(gap)) (N_(RB) ^(DL)) 1^(st) Gap (N_(gap, 1))2^(nd) Gap (N_(gap, 2))  6-10 ┌N_(RB) ^(DL)/2┐ N/A 11  4 N/A 12-19  8N/A 20-26 12 N/A 27-44 18 N/A 45-49 27 N/A 50-63 27  9 64-79 32 16 80-110 48 16

However, in the case where resources are allocated with 12 or 16contiguous PRBs for PRB mapping as in Proposal 1, if an RB gap fordistributed resource allocation in [Table 3] is added, the number ofPRBs may be exceeded and thus resources may not be allocated in somecases. For example, if a system BW includes 27 RBs and a PRB mappingunit is 12 RBs, an RB gap for distributed resource allocation is 18.Then if PRBs #4, #6, #9, and #11 are allocated to a UE, a PRB number towhich the RB gap is added is #29, larger than an actual PRB value.Therefore, there is a need for a table listing different RB gap valuesfrom [Table 3] for 3GPP LTE in the foregoing proposals supporting FDR.

Embodiment 4-1

If RBGs are configured in a PRB mapping rule with four or morecontiguous PRBs for FDR in Proposal 1 and Proposal 2 (Embodiment 1-1),RB gap values may be configured as listed in [Table 4]. [Table 4] is atable listing RB gap values available in an FDR environment.

TABLE 4 System BW Gap (N_(gap) ) (N_(RB) ^(DL)) 1^(st) Gap (N_(gap, 1) )2^(nd) Gap (N_(gap, 2))  6-10 ┌N_(RB) ^(DL)/2┐ N/A 11 4 N/A 12-19 8 N/A20-26 <12 N/A 27-44 <18 N/A 45-49 <27 N/A 50-63 <27 N/A or <9  64-79 <32N/A or <16  80-110 <48 N/A or <16

In a 5G communication system New RAT (NR), an RB gap may be changedaccording to an RBG size which is defined based on a system BW.

The above-described embodiments correspond to combinations of elementsand features of the present invention in prescribed forms. And, therespective elements or features may be considered as selective unlessthey are explicitly mentioned. Each of the elements or features can beimplemented in a form failing to be combined with other elements orfeatures. Moreover, it is able to implement an embodiment of the presentinvention by combining elements and/or features together in part. Asequence of operations explained for each embodiment of the presentinvention can be modified. Some configurations or features of oneembodiment can be included in another embodiment or can be substitutedfor corresponding configurations or features of another embodiment. And,it is apparently understandable that an embodiment is configured bycombining claims failing to have relation of explicit citation in theappended claims together or can be included as new claims by amendmentafter filing an application.

Those skilled in the art will appreciate that the present invention maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent invention. The above embodiments are therefore to be construedin all aspects as illustrative and not restrictive. The scope of theinvention should be determined by the appended claims and their legalequivalents, not by the above description, and all changes coming withinthe meaning and equivalency range of the appended claims are intended tobe embraced therein.

INDUSTRIAL APPLICABILITY

The method and apparatus for allocating resources to an FDR-mode UE in awireless communication system may be used industrially in variouswireless communication systems such as a 3GPP LTE/LTE-A system and a 5Gcommunication system.

1. A method for allocating resources by a base station in a wirelesscommunication system, the method comprising: configuring a ResourceBlock Group (RBG) dependent on whether a user equipment operates in FullDuplex Radio (FDR) mode or Half Duplex (HD) mode; and allocatingresources to the user equipment in units of the configured RBG, whereinthe RBG includes a plurality of Resource Blocks (RBs).
 2. The methodaccording to claim 1, wherein when the user equipment operates in theFDR mode, the RBG is configured as non-contiguous RBs in a frequencydomain.
 3. The method according to claim 2, wherein when the userequipment operates in the HD mode, the RBG is configured as contiguousRBs in the frequency domain.
 4. The method according to claim 3, whereina number of the plurality of RBs in the RBG is 6, 4, 3, or
 2. 5. Themethod according to claim 2, wherein indexes of the non-contiguous RBsare non-contiguous.
 6. The method according to claim 2, wherein thenon-contiguous RBs of the RBG are selected to minimize Inter-ModulationDistortion (IMD) affecting adjacent RBs.
 7. A base station forallocating resources in a wireless communication system, the basestation comprising: a processor configured to: configure a ResourceBlock Group (RBG) dependent on whether a user equipment operates in FullDuplex Radio (FDR) mode or Half Duplex (HD) mode; and allocate resourcesto the user equipment in units of the configured RBG, wherein the RBGincludes a plurality of Resource Blocks (RBs).
 8. The base stationaccording to claim 7, wherein when the user equipment operates in theFDR mode, the processor configures the RBG as non-contiguous RBs in afrequency domain.
 9. The base station according to claim 8, wherein whenthe user equipment operates in the HD mode, the processor configures theRBG as contiguous RBs in the frequency domain.
 10. The base stationaccording to claim 9, wherein the number of the plurality of RBs in theRBG is 6, 4, 3, or
 2. 11. The base station according to claim 8, whereinindexes of the non-contiguous RBs are non-contiguous.
 12. The basestation according to claim 8, wherein the non-contiguous RBs of the RBGare selected to minimize Inter-Modulation Distortion (IMD) affectingadjacent RBs.